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Biomedical subjects

C Knospe

Publications and source records attributed to C Knospe.

At least 19 recordsLinked to original sources
PubMed2003

[Phylogeny, form and function of canine teeth in the horse].

The canine teeth of the horse developed phylogenically from the simple, pointed, short-rooted tooth form of the leaf eating, in pairs living, Eocene horse Hyracotherium and served up to the Oligocene as a means of defense (self preservation). In the Miocene the living conditions of the Merychippus changed and they took to eating grass and adopted as a new behavior the life in a herd. The canine teeth possibly played an important role in fights for social ranking; they changed from a crown form to knife-like shape. In the Pliohippus the canine tooth usually remained in male horses and since the Pliocene, it contributed to the fights between stallions, to ensure that the offspring only came from the strongest animals (preservation of the species). Form and construction of the canine tooth are described and discussed in detail under the above mentioned phylogenic and ethologic aspects.

Animals↗
PubMed2002

[The origin and function of the enamel cup, infundibulum dentis, on the incisors of the horse].

The enamel cups of equids originated phylogenetically through several phases in Oligocene and Miocene horses, which readjusted from hard to soft leaf food and from double nutrition (leaves and grass) to a pure grass intake. This has been proved experimentally. The resulting construction of the incisor is continually changed on its occlusal surface by erosion according to the pattern of the enamel crests. Referring to the whole incisor tooth, this results in an equid life cycle in which the good grip of the occlusal surface and the efficiency of ingestion favours the young, sexually mature horses, which are at the best age for food intake.

Age Factors↗
PubMed2002

Periods and stages of the prenatal development of the domestic cat.

Twenty-two stages of the prenatal development of the domestic cat are described for intraspecies comparison in embryological studies. These are assigned to the 15 embryonal periods based on the Nomina Embryologica Veterinaria to make the interspecies comparison possible.

Animals↗
PubMed2001

[The phylogenesis of equine teeth].

Phylogenetic research on the teeth of equidae beginning with dagger Hyracotherium ('Eohippus') will be summarized, subdivided into its components, analysed in a new way and finally interpreted according to several theories of evolution. In this context, specific cells (ameloblasts, odontoblasts, cementoblasts) are discussed and valued according to Preuss (1987) as active carriers of the evolution of teeth.

Animals↗
PubMed1999

[Evolution and Darwinian theory].

The Darwinian theory today is broadly accepted as one cornerstone of science. However, isn't biology as a life science both, material- and art subject?

Animals↗
PubMed1998

[The development of the horse testis].

The aim of the study was to answer the open questions concerning the development of the horse's testis. This study revealed that the seminiferous tubules originate from the sex cords of the coelomic epithelium and Leydig cells from the proximal part of mesonephric nephrons, whereas the rete and the ductuli efferentes derive from intermediate and distal parts of the mesonephric tubules. During the development the Leydig cells undergo an enormous proliferation due to the PMSG secretion in the mare. The proliferation of these cells prevent the deep penetration of the rete into the medulla and is therefore the reason for the reduced extension of the rete and mediastinum testis in the stallion, although 80% of these cells degenerate in the last third of pregnancy. The growth of the seminiferous tubules during sexual maturity reduces the rete to the extremitas capitata of the testis.

Animals↗
PubMed1997

Histochemical demonstration of lipase activity in the gastric mucosa of the cat.

The aim of the present study was to determine, histochemically, the onset and location of production of preduodenal lipase in fetal, suckling, weaned and adult cats. Strong enzymatic activity was localized in the surface mucous cells of the gastric mucosa in animals at postpartal day 1 after ingestion of milk. Activity of gastric lipase persisted as long as animals were nursed. No gastric lipase could be demonstrated in weaned and adult cats. Lingual lipase was not found at any developmental stage examined. Thus, in the newborn cat, lipase of the gastric mucosa is responsible for milk fat lipolysis.

Aging↗
PubMed1997

[Observations on epidural anesthesia in cats from the anatomical viewpoint].

The topographic-anatomical situation of the conus medullaris and the cauda equina in cats is shown: in about two thirds of the cases the conus medullaris at least reaches the level of the first sacral vertebra. As far as the site of the epidural injection is concerned the sacrococcygeal space or the first intercoccygeal space are proposed in order to avoid damage to the spinal cord. When seeking the site of injection it is advantageous to orientate oneself by following the sacral processus spinosi in caudal direction beginning with the lumbosacral space. In case of adipose animals the first intercoccygeal space can be palpated by moving the tail up and down. Both sites are equivalent. The volume to be injected varies between 0.3 and 0.9 ml solution per cat depending on the needs.

Anesthesia, Epidural↗
PubMed1996

[Development of the gastric glands of cats (Felis silvestris catus)].

There are five stages in the development of the cat's gastric glands: 1. During the stage of the indifferent epithelium from day 19 to day 24, the anlage of the stomach develops with all layers; 2. The stage of gland formation from day 24 to day 41 is the beginning of the gland buds. They develop in connection with endocrine cells on day 34 into primitive oxyntic and primitive mucous cells. The latter form the basis for all other cells, including the surface mucous cells; 3. During the stage of gland evagination from day 42 to 55, the anlagen are separated into primitive pits and tubules, while the cells continue to differentiate and the first intermediate cells are seen; 4. The stage of gland branching from day 56 to birth is characterized by the formation of additional glands at the bottom of the pits which change the ordinary anlagen into branched glands. During this stage, the cardiac glands are formed; 5. In the stage of gland maturation from birth to the 9th week, the peptic cells are formed and the glands start functioning. The oxyntic cells show carbonic-anhydrase activity and signs of acid secretion, and, between the weeks 4 and 8, the peptic cells contain pepsinogen, producing a negative reaction to PAS and a positive reaction to HID. Mucous cells and mucous neck cells produce PAS- and AB-positive mucin.

Aging↗
PubMed1995

[Prenatal development of the mandibular gland and parotid gland in cats].

The prenatal development of the cat's mandibular and parotid gland was examined by means of serial section of 36 cat embryos at 14-62 days of development. Both glands were excised from the epithelium of the primitive oral cavity and branched up to day 36 of the branching phase into a specific connective tissue. This tissue contained besides fine collagenous fibres, a high amount of proteoglycans. In the subsequent separation phase, ducts and acini differentiated themselves in primitive lobules which were separated by connective tissue. In the prenatal differentiation phase, from about day 50 up to birth, intercalated ducts and striated ducts were formed. In the acini, mucous and serous cells contained different amounts of complex carbohydrates. This secretory component changed shortly before birth.

Animals↗
PubMed1994

[The temporomandibular joint of the domestic cat (Felis silvestris catus)].

The mandibular joint of the cat is an incongruent cylindrical joint, which works as a hinge or screw joint. The course of motion is unilateral in the plane of the cutting edge of the molar/premolar border [symbol: see text]. The articular disc is a connective tissue membrane; its new function is decreasing the friction.

Animals↗
PubMed1994

Development of spatial relations of shoulder and brachium in embryonal chick wing.

The linear marking method was employed to study morphogenetic movements of tissues involved in the development of the definitive position and shaping of the shoulder and arm. Chick embryos in the range of embryonal day 3.5 to 4.5 were used with the following results: -Asymmetrical growth of the early wing bud and the oblique position of humerus anlage in the early wing bud as proposed by Saunders (1948) and Seichert (1965) were confirmed. -It was found that the cranial ascend of the shoulder (Seichert and Knospe 1992) is accompanied by the slight ventromedial rotation of the complex consisting of the scapula and coracoid. -Torsion along the longitudinal axis of the stylopodium was observed: the proximal part of the stylopodium (both the humerus anlage and related soft tissues) moves in the sense of supination, the distal part moves in the sense of pronation.

Animals↗
PubMed1992

[Is there an internal tongue musculature in parrots?].

The result of this study shows that the tongue of the parrot has voluntary muscle that runs dorsally to the apex of the tongue. This musculature can be regarded as evidence that a reduced internal musculature exists.

Animals↗
PubMed1992

[Prenatal development of the horse ovary].

To answer the many open questions concerning the development of the horse's ovary, first the prenatal development was investigated. It resulted that follicles derive from the germinal epithelium and its cords, whereas the Leydig cells and the rete blastema originate from the mesonephros. In the second third of pregnancy the Leydig cells undergo an enormous proliferation, in the last third they degenerate. However this degeneration is not connected with the postnatal development of the ovulation groove.

Animals↗
PubMed1992

The rearrangement of the cranial part of embryonal body in chick studied by linear marking. II. Relations of the neck, thorax and shoulder.

The linear marking method was employed for studying morphogenetic movements of tissues involved in formation of the cranial part of the chick embryonic body. A total of 120 chick embryos marked on days 3-5 were used in this study with the following results: The cranial shift of axial structures and somites with respect to the other components of the cranial part of the embryonic body, described in our earlier papers, has been proven. This shift is considered crucial from the point of understanding and proper interpretation of the following formative processes: The prospective mesenchyme of the wall of the thorax shifts continuously in the cranial direction. The rate of the shift of the mesenchyme in the dorsal part of the developing body wall appears considerably lower than that of the somites. The cranial shift of the mesenchyme of the ventral part of the body wall is directed ventromedially and proceeds more rapidly than in the dorsal part of the body wall. The ventromedial deviation of the cranial shift is gradually increased in the craniocaudal sequence. In this way, the mesenchyme of the lateral body wall replaces step by step the membrana reunions to cover the heart, rapidly growing lungs and the liver. The presumptive shoulder shifts cranially at the rate similar to that of the somites. In this way, the shoulder slides over the body wall mesenchyme formerly located in the more cranial position. The shoulder undergoes rotation by the mechanism which is discussed.

Animals↗
PubMed1991

The topogenesis of the thyroid in chick embryos.

Using the technique of linar marking on the embryonic thyroid of chicken, it was proven that the thyroid anlage after its evagination from the primitive pharynx, does not undergo any caudal migration. Its topogenesis is influenced by two main mechanisms. First, the relative craniocaudal displacement follows from the cranially oriented growth of the neck and second, the enlarging oesophagus presses the trachea ventrally against the thyroid anlage promoting its division and separation of both lobes.

Animals↗